Method and system for communicating DisplayPort and single-link DVI/HDMI information for dual-mode devices

ABSTRACT

A system and method for communicating DVI (digital visual interface) and HDMI (high-definition multimedia interface) information is provided. The system includes a local unit operable to produce a downstream request packet in reaction to received DVI or HDMI information from a video source device and to transmit the request packet to a remote unit via a first simplex channel of a communications link. The remote unit operates to produce an upstream reply packet in reaction to received DVI or HDMI information by the remote unit from a video sink device and to transmit the reply packet to the local unit via a communications link. The system allows greater distances and allows various communications mediums to be used between the source and sink, and can communicate DVI and HDMI information and other information via a variety of different communications links.

FIELD OF THE INVENTION

This invention relates to methods and system for communicating the DVI(digital visual interface) and HDMI (high-definition multimediainterface) Display Data Channel, Hot Plug Detect and Cable AdapterDetect signals for, and between, Dual-mode Devices (DisplayPort and DVIand/or HDMI) over a variety of link mediums and communication protocols.

DESCRIPTION OF THE PRIOR ART

The VESA (Video Electronics Standards Association) DisplayPort Standarddefines a scalable digital display interface, with optional audio andcontent protection capabilities for broad applications within PC andconsumer electronic (CE) devices. The DisplayPort interface is designedto support both internal chip-to-chip and external box-to-box digitaldisplay connections. Potential internal chip-to-chip applicationsinclude usage within a notebook PC for driving a panel from a graphicscontroller, or usage within a monitor or TV for driving the displaycomponent from a display controller, for example. Examples of box-to-boxapplications for DisplayPort interface connections include displayconnections between PCs and monitors, projectors, and TV displays.DisplayPort is also suitable for display connections between consumerelectronics devices such as high-definition optical disc players, settop boxes, and television displays. The standard currently includesVersion 1.1, 1.1a and 1.2 levels.

The DisplayPort Interoperability Guideline within the DisplayPortStandard was designed to realize interoperability between DisplayPortand other display interfaces (DVI, HDMI etc.) through the use of cableadapters. Devices that support both DisplayPort 1.1a and either DVI 1.0or HDMI specifications are considered to be Dual-mode devices. Throughthe use of a cable adapter, a Dual-mode “source” device can interoperatewith a DVI 1.0/HDMI “sink” device.

Similarly, through the use of a cable adapter, a DVI 1.0/HDMI sourcedevice can interoperate with a Dual-mode sink device.

There are two types of cable adapter defined by the guideline. In afirst type of cable adapter, a source-side cable adapter is one in whicha DisplayPort interface is presented on the source (upstream) side ofthe device and an alternative video interface is presented on the sink(downstream) side of the device. In a second type, a sink-side cableadapter is one in which a DisplayPort interface is presented on the sink(downstream) side of the device and an alternative video interface ispresented on the source (upstream) side of the device.

When a cable adapter is implemented as a discrete unit, a source-sideadapter can support a DisplayPort cable interface at its upstream portfor attachment to a Dual-mode source device, and provides a DVI/HDMIcable interface at its downstream port for attachment to a DVI/HDMI sinkdevice. In a similar manner, a sink-side adapter can support aDisplayPort cable interface at its downstream port for attachment to aDual-mode sink device, and provides a DVI/HDMI cable interface at itsupstream port for attachment to a DVI/HDMI source device.

In applicant's U.S. patent application Ser. No. 12/750,427, the contentsof which are incorporated herein by reference, a method and system forcommunicating DisplayPort information was provided which enabledDisplayPort Auxiliary Channel information and Hot Plug Detect (HPD)information to be transmitted over a variety of link mediums with avariety of communication protocols. However, that application did notaddress a situation which would enable Dual-mode DisplayPort devices tooperate over a variety of link mediums and with a variety ofcommunication protocols.

Further, it should be noted that the prior art systems include a commondedicated wire that enables the source and sink device to determineshared timing information. Since such a dedicated wire is not availablein the current application, it would be advantageous to be able toprovide a substitute method for timing control.

SUMMARY OF THE INVENTION

The use of DisplayPort cable adapters enables DisplayPort devices tooperate in a system with a variety of legacy devices such as those basedupon the earlier DVI and HDMI standards. Accordingly, while theDisplayPort communication links and methods described in U.S. patentapplication Ser. No. 12/750,427 have proven useful in homogenouspopulations of DisplayPort devices, it would still be desirable toprovide improvements to the technology to enable non-DisplayPort devicesto be introduced to the system and to operate across a variety of linkmediums and with a variety of communication protocols.

Accordingly, the current invention provides methods and apparatuseswhich enable the Display Data Channel (DDC), Hot Plug Detect (HPD) andCable Adapter Detect (CA_DET) signals (from now on collectively referredto as “Dual-mode signals”) to be packetized and communicated overvarious link mediums. In a preferred embodiment, the present inventionalso provides devices which will enable these Dual-mode signals tooccupy, concurrently, the same link medium that is also occupied byforeign device information. Examples of such foreign device informationinclude data communications from USB, Ethernet and other datacommunication protocols.

An advantage of the present invention's ability to allow connectivity toany suitable link medium is realized when, for example, a purely opticallink is desired for all, or a portion of the link between a Dual-modedevice and a Dual-mode cable adapter, either for electrical isolation orthe desire to support longer transmission distances. In this situation,all of the main link pairs can be easily mapped to laser diodes tooptically transmit on the source side, and photodiodes to receive on thecable adapter or sink side. The DDC, however, cannot be easily mapped toan optical interface because it is a half-duplex protocol. If DDC couldbe converted to a full-duplex link protocol then the ability to maintaina completely optical link in the data transmission connection, could beaccomplished. Another advantage of the present invention's ability toallow connectivity to any suitable link medium is realized whenDual-mode signals are embedded into another communications protocol,such as Ethernet.

According to the present invention, a system for communicating videoinformation in a Dual-mode environment includes: (i) a local unit forproducing an incoming request packet in response to DVI or HDMIinformation, received by the local unit of the system (from either a DVIor HDMI or Dual-mode source device), and transmitting the incomingrequest packet to a remote unit of the system via a first simplexchannel of a dual simplex communications link; and (ii) a remote unitfor producing an incoming response packet in response to a DVI or HDMIor Dual-mode sink unit and transmitting the response packet to the localunit via a second simplex channel of the dual simplex communicationslink, wherein a communication link is provided between the local unitand the remote unit.

The local unit may optionally comprise a device for storing responsesfrom the remote unit, and may also include a method to select responseinformation stored at the local unit or response information receivedfrom the remote unit. The local unit may optionally include foreigndevice local transmitting means for producing foreign device downstreamdata in response to foreign device information received by the localunit from a foreign device and transmitting the foreign downstream datato the remote unit via the first simplex channel.

The remote unit may include remote outputting methods for outputting bythe remote unit a representative DVI or HDMI information. The remoteunit may include foreign remote transmitting means for producing foreignupstream data in response to foreign destination information received bythe remote unit from a foreign destination device and transmitting theforeign upstream data to the local unit via the second simplex channel.

It is an objective of the present invention to provide methods andsystems to provide a method of communicating Dual-mode Device data sothat it can be packetized and distributed over various link mediums andlengths.

It is a further object of the present invention that the methods andsystem should preferably accommodate any transmission delays which areintroduced by various link mediums and lengths.

It is a further object of the present invention that foreign devicedata, unrelated to Dual-mode data, may be transported across the linkmedium in addition to the Dual-mode data.

It is a further object of the present invention that the system may beconnected to either a source-side cable adapter or a sink-side cableadapter.

It is a further object of the present invention that no changes arerequired to the DisplayPort source device or Dual-mode source device.

It is a further object of the present invention that no changes arerequired to the DisplayPort sink device or Dual-mode sink device.

It is a further object of the present invention that no changes arerequired to either the source-side cable adapter or the sink-side cableadapter.

It is a further object of the present invention that a plurality ofDisplayPort devices and Dual-mode devices may be connected to thesystem.

As such, in a first aspect, the present invention provides a method forcommunicating DisplayPort dual-mode signals and information between anoriginating unit and a terminating unit across a communications link(which is preferably a dual simplex communication link), and through aDisplayPort dual-mode cable adapter, said method comprising:

-   -   a) receiving at a local unit, (DisplayPort) dual-mode signals        from an originating unit;    -   b) converting at said local unit said received dual-mode signals        into one or a plurality of request data packets;    -   c) transmitting at said local unit said one or a plurality of        request data packets to a remote unit across said (dual simplex)        communications link;    -   d) receiving at said remote unit said transmitted one or        plurality of request data packets as one or a plurality of        received request data packets;    -   e) converting at said remote unit said one or a plurality of        received request data packets into converted dual-mode signals;    -   f) transmitting at said remote unit said converted dual-mode        signals to a terminating unit;    -   g) receiving at said remote unit dual-mode signals from said        terminating unit;    -   h) converting at said remote unit said received dual-mode        signals into one or a plurality of response data packets;    -   i) transmitting at said remote unit said one or a plurality of        response data packets to said local unit across said (dual        simplex) communications link;    -   j) receiving at said local unit said transmitted one or a        plurality of response data packets as one or a plurality of        received response data packets;    -   k) converting at said local unit said one or a plurality of        received response data packets into converted dual-mode signals;        and    -   l) transmitting at said local unit said converted dual-mode        signals to said originating unit,    -   wherein, when said Cable Adapter is a Source Side Cable Adapter,        said terminating unit includes said cable adapter, and when said        cable adapter is a Sink-Side Cable Adapter, said originating        unit includes said cable adapter.

The originating unit is typically a DisplayPort Source device or aDVI/HDMI Source device, and the terminating unit is typically aDisplayPort Sink device or a DVI/HDMI Sink device, and the cable adaptercan be a Source-Side Cable adapter, or a Sink-Side Cable adapter. Whenthe terminating unit is a DVI/HDMI sink, a Source-Side Cable Adapter isused, and both the local unit and remote units are placed between theoriginating unit, and the cable adapter.

When the originating unit is a DVI/HDMI source, a Sink-Side CableAdapter is used, and the local and remote units are both placed betweenthe cable adapter, and the terminating unit.

The local unit is always placed so as to be closer to the originatingdevice than the remote device.

In a further aspect, the present invention also provides a system forcommunicating DisplayPort dual-mode signals and information between anoriginating unit and a terminating unit across a preferably, dualsimplex communications link, in accordance with the method describedhereinabove, said system comprising:

-   -   a) a local unit comprising a local controller operable to:        -   a) receive from an originating unit dual-mode signals;        -   b) convert said received dual-mode signals into one or a            plurality of request data packets;        -   c) transmit said one or a plurality of request data packets            to a remote unit across said (dual simplex) communications            link;        -   d) receive one or a plurality of response data packets from            said remote unit across said (dual simplex) communications            link;        -   e) convert said received one or a plurality of response data            packets into converted dual-mode signals; and        -   f) transmit said converted dual-mode signals to said            originating unit; and    -   b) a remote unit comprising a remote controller operable to:        -   a) receive said one or a plurality of request data packets            from said local unit across said (dual simplex)            communications link;        -   b) convert said received one or plurality of request data            packets into converted dual-mode signals;        -   c) transmit said converted dual-mode signals to a            terminating unit;        -   d) receive from said terminating unit dual-mode signals;        -   e) convert said received dual-mode signals into said one or            a plurality of response data packets; and        -   f) transmit said one or a plurality of response data packets            across said dual simplex communications link.

The local and remote units are preferably connected one to the other, bya dual simplex communications link, although other communication linksmight also be used.

In a still further aspect, the present invention also provides acomputer program product comprising computer-executable instructionsembodied in a computer-readable medium for controlling one or moreprocessors of a local unit connected to a remote unit via a preferablydual simplex, communications link, (the dual simplex communications linkpreferably having first and second simplex channels) to carry out thefollowing steps:

-   -   a) Receiving dual-mode signals from an originating unit;    -   b) Producing a request data packet in response to said dual-mode        signals;    -   c) Storing dual-mode information in memory;    -   d) Determining whether to produce and output to said originating        unit stored dual-mode information stored in memory or to        transmit said request data packet to the remote unit via the        first simplex channel;    -   e) Receiving a response data packet from the remote unit via the        second simplex channel;    -   f) Producing dual-mode signals in response to said response data        packet and outputting to said originating unit said dual-mode        information;    -   g) Receiving foreign information from a foreign source device;    -   h) Producing foreign request data packets in response to said        foreign information; and    -   i) Transmitting said foreign request data packets to the remote        unit via the first simplex channel.

Similarly, the present invention also provides a computer programproduct comprising computer-executable instructions embodied in acomputer-readable medium for controlling one or more processors of aremote unit connected to a local unit via a preferably dual simplexcommunications link (the dual simplex communications link having firstand second simplex channels), to carry out the following steps:

-   -   a) Creating read requests and outputting said requests to a        terminating unit;    -   b) Transmitting the responses to said read requests to the local        unit via the second simplex channel;    -   c) Receiving request data packets from said local unit via the        first simplex channel;    -   d) Producing dual-mode signals in response to said request data        packets from said local unit;    -   e) Outputting said dual-mode signals to a terminating unit;    -   f) Receiving dual-mode signals from said terminating unit;    -   g) Producing a response data packet in response to said        dual-mode signals;    -   h) Transmitting said response data packet to the local unit via        the second simplex channel;    -   i) Receiving foreign request data packets from the local unit        via the first simplex channel;    -   j) Producing foreign information in response to said foreign        request data packets; and    -   k) Outputting said foreign information to a foreign destination        device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the present invention is its application in avideo display environment. As such, details of the invention will bedescribed with particular reference to video communication systems.However, the skilled artisan will appreciate that the system of thepresent invention might also be used in non-video applications.

In one preferred embodiment of a video communication system of thepresent invention, the video source device can be any standard unit ordevice that supports the DisplayPort Dual-mode specifications, such ascomputer graphics cards or video adapters. Preferably the unit or deviceshall support the most recent version of the DisplayPort Dual-modespecifications, but units or devices that support only early versions ofthe DisplayPort Dual-mode specifications are also permissible.

In a further preferred embodiment of a video communication system, thevideo sink device can be any standard unit or device that supports theDisplayPort Dual-mode specifications, such as computer monitors, TVs,projectors, or other video displays. Preferably the unit or device shallsupport the most recent version of the DisplayPort Dual-modespecifications, but units or devices that support only early versions ofthe DisplayPort Dual-mode specifications are also permissible.

In one preferred embodiment of a duplex communications link, the duplexcommunications link is a point-to-point link connected between a localproxy unit and a remote proxy unit.

In a further embodiment of a duplex communications link, the duplexcommunications link is comprised of a shared network that may carryother traffic in addition to the DisplayPort Dual-mode traffictravelling between the source device and the sink device. Networks suchas those based on wired Ethernet, wireless Ethernet, the publicInternet, private intranets and combinations of these networks are, forexample, suitable for this application.

In a yet further embodiment of a duplex communications link, the duplexcommunications link can, when required, operate in half-duplex modewherein information may be transmitted in only one direction at a time.

In a yet further embodiment of a duplex communications link, the duplexcommunications link can operate in full-duplex mode wherein informationmay be transmitted in both directions at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of this invention will now be described by way of exampleonly in association with the accompanying drawings in which:

FIG. 1 is a block diagram of a video communication system incorporatinga source-side cable adapter in a Dual-mode environment according to theprior art;

FIG. 2 is a block diagram of a video communication system incorporatinga sink-side cable adapter in a Dual-mode environment according to theprior art;

FIG. 3 is a block diagram of a system in accordance with the presentinvention, for communicating video information between a source devicecompatible with the DisplayPort specifications for Dual-mode devices anda sink device that is not compatible with the DisplayPort Specificationsacross a dual-simplex communication link;

FIG. 4 is a block diagram of a system for communicating videoinformation between a source device that is not compatible with theDisplayPort specifications and a sink device compatible with theDisplayPort Specifications across a dual-simplex communication link,according to the current invention;

FIG. 5 is a block diagram showing the configuration of the cable-detectsignals when no source or sink-side cable adapters are attached,according to the current invention;

FIG. 6 is a block diagram showing the configuration of the cable-detectsignals when a source-side cable adapter is attached to the downstreaminterface of the system, according to the current invention;

FIG. 7 is a block diagram showing the configuration of the cable-detectsignals when a sink-side cable adapter is attached to the upstreaminterface of the system, according to the current invention;

FIG. 8 is a timing diagram showing one method for stretching the DDCclock, according to the current invention;

FIG. 9 is a timing diagram showing a second method for stretching theDDC clock, according to the current invention;

FIG. 10 is a timing diagram showing a third method for stretching theDDC clock, according to the current invention;

FIG. 11 is a sequence diagram showing a method for stretching the DDCclock during a Read transaction, according to the current invention;

FIG. 12 is a sequence diagram showing a method for stretching the DDCclock during a Write transaction, according to the current invention;

FIG. 13 is a block diagram of a system for communicating videoinformation between a source device compatible with the DisplayPortspecifications for Dual-mode devices and a sink device that is notcompatible with the DisplayPort Specifications across a duplexcommunication link wherein foreign data may be combined with theDisplayPort Dual-mode signals, according to the current invention;

FIG. 14 is a block diagram of a system for communicating videoinformation between a source device that is not compatible with theDisplayPort specifications and a sink device compatible with theDisplayPort Specifications across a duplex communication link whereinforeign data may be combined with the DisplayPort Dual-mode signals,according to the current invention; and

FIG. 15 is a block diagram of a system for multiplexing andde-multiplexing (interleaving) of foreign device information with theDisplayPort Dual-mode signals, according to the current invention.

DETAILED DESCRIPTION OF THE INVENTION

The novel features which are believed to be characteristic of thepresent invention, as to its structure, organization, use and method ofoperation, together with further objectives and advantages thereof, willbe better understood from the following drawings in which a presentlypreferred embodiment of the invention will now be illustrated by way ofexample only. In the drawings, like reference numerals depict likeelements.

It is expressly understood, however, that the drawings are for thepurpose of illustration and description only and are not intended as adefinition of the limits of the invention.

In the drawings, FIG. 1 provides a prior art block diagram showing aDual-mode environment (1), consisting of a DisplayPort Dual-mode sourcedevice (2) connected to a DVI or HDMI sink device (4) through asource-side cable adapter (3). The Dual-mode source device (2) containsa DisplayPort connector (5) which connects to a DisplayPort connector(7) of the source-side cable adapter (3) through a DisplayPort Cable(6). The DVI or HDMI sink device (4) contains a DVI or HDMI connector(10) which connects to the DVI or HDMI connector (8) of source-sidecable adapter (3) through a DVI or HDMI cable (9). Upon attaching thesource-side cable adapter (3) to the Dual-mode source device (2), theCable Adapter Detect (CA_DET) signal (14) is asserted to indicate to thesource device (2) that it is attached to the cable adapter (3) and thatthe source device is required to operate by transacting DVI or HDMIinformation (Display Data Channel (DDC) data and DVI/HDMI video stream).Upon attaching the DVI or HDMI sink device (4) to the cable adapter (3),the Hot Plug Detect (HPD) signal (14) is asserted to indicate that thesink device is attached. The HPD signal is passed through to the sourcedevice (2). The source device (2) may transact Display Data Channel(DDC) information through pass-through DDC signals (13) in the cableadapter (3) to the sink device (4) and will transmit video informationthrough the pass-through main link (11) in the cable adapter (3) to thesink device (4).

FIG. 2 provides a prior art block diagram showing an alternate Dual-modeenvironment (15), consisting of a DVI or HDMI source device (16)connected to a DisplayPort Dual-mode sink device (18) through a sinkside cable adapter (17). The Dual-mode sink device (18) contains aDisplayPort connector (24) which connects to the DisplayPort interface(22) of the sink-side cable adapter (17) through a DisplayPort Cable(23). The DVI or HDMI source device (16) contains a DVI or HDMIconnector (19) which connects to the DVI or HDMI interface (21) ofsink-side cable adapter (17) through a DVI or HDMI cable (20). Uponattaching the sink-side cable adapter (17) to the Dual-mode sink device(18), the CA_DET signal (28) is asserted to indicate to the sink device(18) that it is attached to a cable adapter (17) and that the sinkdevice is required to operate by transacting DVI or HDMI information. Atthis time, the HPD signal (26) is asserted to indicate a sink device isattached. The HPD signal is passed through to the source device (16).The source device (16) may transact DDC information through pass-throughDDC signals (27) in the cable adapter (17) to the sink device (18) andwill transmit video information through the pass-through main link (25)in the cable adapter (17) to the sink device (18).

Referring to FIG. 3, the system according to a first embodiment of theinvention is shown generally at (29). The system (29) functions tocommunicate DVI or HDMI information along a communications link (32).The communications link (32) may be any wired or wireless connectionsuitable for transmitting data or other electronic signals, and mayinclude a copper wire link, a coaxial cable link, a fiber-optictransmissions link, a radio link, a cellular telephone link, a satellitelink, a line-of-sight free optical link, and any combination thereof,for example. Preferably, the communications link (32) permitssimultaneous two-way communications, such as by implementing afull-duplex or dual simplex medium. The communications link (32) isshown as implementing a dual simplex medium having one channel (33)intended for one-way communications in one direction and another channel(34) intended for one-way communication in the opposing direction.

System (29) includes a local proxy unit (LPU) (30) and a remote proxyunit (RPU) (31) operable to effect communications between each other viathe communications link (32). In this context, the term “local” refersto the unit closest to the source device, and the term “remote” refersto the unit closest to the sink device, regardless of the positioning ofthe cable adapter (source-side or sink-side).

In the first embodiment, the invention advantageously permits, over theprior art system shown in FIG. 1, the communication of Dual-mode signals(DVI or HDMI information) between a DisplayPort Dual-mode source device(2) and a DVI or HDMI sink device (4) via a source-side cable adapter(3) which may be separated from the Dual Mode Source (2) by a distancebeyond current specifications; advantageously permits the communicationof Dual-mode signals between the DisplayPort Dual-mode source device (2)and DVI or HDMI sink device (4) via a source-side cable adapter (3) viaone or more of a variety of different types of communications links(32); or both advantageously permits the communication of Dual-modesignals over a distance beyond current specifications and via a varietyof different types of communications link (32).

In more detail, the DVI/HDMI sink device (4) is attached to thesource-side cable adapter (3) via the DVI/HDMI connectors (10 & 8) onboth respective devices with a DVI/HDMI cable (9). The source-side cableadapter (3) is connected to the RPU (31) by a DisplayPort Connector (7)attached to the source-side cable adapter (3), through a DisplayPortcable (6) to the DisplayPort interface (52) located on the RPU (31). TheRPU (31) consists of the remote main link channel (46), the remote HotPlug Detect (HPD) channel (49), the remote Display Data Channel (DDC)(50), the remote Cable Adapter Detect (CA_DET) channel (51), the remotecontroller (48), and the link medium channel (47).

The remote link medium channel (47) bi-directionally directs link mediuminformation signals such as link medium data between the remote linkmedium interface (45) and the remote controller (48).

The remote controller (48) includes a remote processor (49) whichfunctions to control features and implement methods of the system,including converting the format of data between DVI/HDMI information andthat of a protocol specific to a given communications link Preferably,the LPU (30) and RPU (31) operate compatibly such that the remotecontroller (48) converts request packets from the LPU (30) into theappropriate format to be outputted at the remote DisplayPort interface(52). The remote controller also functions to convert the informationpresent at the remote DisplayPort interface (52) (such as DDC, HPD, orCA_DET) into a response packet format specific to a given communicationslink (32).

The LPU (30) connects to the communications link (32) by means of alocal link medium interface (44). The local link medium channel (43)bi-directionally directs link medium information signals such as linkmedium data between the local link medium interface (44) and the localcontroller (40). The LPU (30) also consists of the local main linkchannel (36), the local HPD channel (37), the local DDC (38) and theCA_DET channel (39). The local controller (40) includes a localprocessor (41) which functions to control features and implement methodsof the system, including converting the format of data between DVI/HDMIinformation and that of a protocol specific to a given communicationslink (32). The local controller (40) also functions to convert theinformation present at the local DisplayPort interface (35) (such as DDCor CA_DET) into a request packet format specific to a givencommunications link (32). The local controller (40) also includes alocal memory (42) which stores response data sent by the RPU (31). Thelocal processor (41) may retrieve data from the memory to send to thelocal DisplayPort interface (35).

Upon connection of the RPU (31) to the source-side cable adapter (3),the source-side cable adapter (3) indicates over the remote CA_DETchannel (51) via the DisplayPort interface (52) that a cable adapter ispresent. The remote controller (48) creates a CA_DET event packet to betransmitted through the communications link (32) via the remote linkmedium channel (47) and the remote link medium interface (45). The localcontroller (40) within LPU (30) receives the CA_DET event packet via thelocal link medium channel (43) and local link medium interface (44) andindicates on the local CA_DET channel (39) that a cable adapter ispresent. This signal is transmitted to the DisplayPort Dual-mode sourcedevice (2) via the DisplayPort connector (5), source side DisplayPortcable (6) and local DisplayPort interface (35).

Upon connection of the DVI/HDMI sink device (4) to the system (29), thesink device (4) indicates, through source-side cable adapter (3), andthen to the remote HPD channel (49) that a sink device is present. Theremote controller (48) creates a HPD event packet to be transmittedthrough the communications link (32) via the remote link medium channel(47) and the remote link medium interface (45). The local controller(40) within LPU (30) receives the HPD event packet via the local linkmedium channel (43) and local link medium interface (44) and indicateson the local HPD channel (37) that a DVI/HDMI sink device is present.This signal is transmitted to the DisplayPort Dual-mode source device(2).

It should be noted that the local DDC (38) directs DDC data and DDCclock signals bi-directionally between the local DisplayPort interface(35) and the local controller (40). However, the local controller (40)preferably can implement clock stretching by holding the DDC clock low,dependant on the type of DDC transaction, in order to allow the localcontroller (40) to create a request packet to be transmitted through thecommunications link (32) via the local link medium channel (43) and thelocal link medium interface (44). The remote controller (48) within RPU(31) receives the request packet from the LPU (30) via thecommunications link (32), the remote link medium interface (45) and theremote link medium channel (47). The remote controller (48) converts therequest packet into DDC data format and transmits the information to theremote DisplayPort interface (52) via the remote DDC (50). The remotecontroller (48) receives information from the remote DisplayPortinterface (52) and converts the information into a response packet. Theresponse packet is directed to the remote link medium interface (45) viathe remote link medium channel (47). The local controller (40) withinLPU (30) receives the response packet from the RPU (31) via thecommunications link (32), the local link medium interface (44) and thelocal link medium channel (43). The local controller (40) disables theDDC clock stretching and converts the response packet into DDC dataformat and transmits the information to the local DisplayPort interface(35) via the local DDC (38).

Additionally, the remote controller (48) within RPU (31), upon receivingan indication over the remote HPD channel (49) that a sink device ispresent, may create DDC read commands to send to the sink device inorder to read static DDC information. The remote controller (48)receives responses to these read commands and generates response packetsto be transmitted to the LPU (30). The LPU (30) receives these packetsvia the communications link (32) and the local controller (40) storesthis information in the local memory (42). Upon receiving DDC readcommands at the local DisplayPort Interface (35) pertaining to thisinformation, the local controller (40) may select the stored informationin the local memory (42) and transmit the DCC information to theDisplayPort interface (35) via the local DDC (38).

The local main link channel (36) is operable to direct visualinformation signals in a downstream direction from the local DisplayPortinterface (35) to a local link medium interface (44) of the LPU (30).For example, when the local DisplayPort interface (35) receives DVI/HDMIinformation from the DisplayPort Dual-mode source device (2) thatincludes an uncompressed digital packetized video stream according tothe DVI/HDMI specification, the local DisplayPort interface (35) directssuch video stream to the local main link channel (36) for delivery tothe local link medium interface (44). The remote main link channel (46)is operable to direct visual information signals in a downstreamdirection from the remote link medium interface (45) to a remoteDisplayPort interface (52) of the RPU (31). By way of example, when theRPU (31) receives the video stream from the LPU (30) via thecommunications link (32), the remote link medium interface (45) directsthe video stream to the remote main link channel (46) for delivery tothe remote DisplayPort interface (52).

Referring to FIG. 4, a system according to a second embodiment of theinvention is shown generally at (53). The second embodiment of theinvention advantageously, over the prior art system shown in FIG. 2,permits the communication of Dual-mode signals (DVI or HDMI information)between a DVI/HDMI source device (16) and a DisplayPort Dual-mode sinkdevice (18) via a sink-side cable adapter (17) which may be separated bya distance beyond current specifications; advantageously permits thecommunication of Dual-mode signals between the DVI/HDMI source device(16) and DisplayPort Dual-mode sink device (18) via a sink-side cableadapter (17) via one or more of a variety of different types ofcommunications links (32); or both advantageously permits thecommunication of Dual-mode signals over a distance beyond currentspecifications and via a variety of different types of communicationslink (32).

In more detail, the DVI/HDMI source device (16) is attached to thesink-side cable adapter (17) via the DVI/HDMI connectors (19 & 21) onboth respective devices with a DVI/HDMI cable (20). The sink-side cableadapter (17) is connected to the LPU (30) by a DisplayPort Connector(22) attached to the sink-side cable adapter (17), through a DisplayPortcable (23) to the DisplayPort interface (35) located on the LPU (30).The LPU (30) and RPU (31) each consist of the same elements as describedin FIG. 3.

The CA_DET channels (39 & 51) on the LPU and RPU operate differentlycompared to the embodiment shown in FIG. 3. In this embodiment, uponconnection of the LPU (30) to the sink-side cable adapter (17), thecable adapter indicates over the CA_DET channel (39) that a cableadapter is present. The local controller (40) within LPU (30) creates aCA_DET event packet to be transmitted through the communications link(32) via the local link medium channel (43) and the local link mediuminterface (44). The remote controller (48) within RPU (31) receives theCA_DET event packet via the remote link medium channel (47) and remotelink medium interface (45) and indicates on the remote CA_DET channel(51) that a cable adapter is present. This signal is transmitted to theDisplayPort Dual-mode sink device (18) via the DisplayPort connector(24), sink-side DisplayPort cable (23), and local DisplayPort Interface(52).

All other aspects of this embodiment operate in the same fashion as thatshown and described in respect of FIG. 3.

FIG. 5 is a block diagram showing the configuration of the cable-detectsignals when no source or sink-side cable adapters are attached,according to the current invention. Referring to FIG. 5, and as seen inFIGS. 3 and 4, the local and remote CA_DET channels (39 & 51) on the LPU(30) and RPU (31) are operable bi-directionally. When neithersource-side cable adapter nor sink-side cable adapter is present ateither local or remote DisplayPort interface (35 & 52), the local andremote CA_DET channels (39 & 51) are both configured in a default inputdirection towards the local and remote controllers (40 & 48).

FIG. 6 is a block diagram showing the configuration of the cable-detectsignals when a source-side cable adapter (3) is attached to thedownstream interface of the system shown in FIG. 5. FIG. 6 depicts asource-side cable adapter (3) connected to the RPU (31) via DisplayPortconnector (7), DisplayPort cable (6) and remote DisplayPort interface(52). The remote CA_DET channel (51) is asserted by the source-sidecable adapter (3), and the remote controller (48) observes that a cableadapter is connected. The remote controller (48) generates and transmitsa CA_DET event packet to the LPU (30) via the remote link medium channel(47) and remote link medium interface (45). The LPU (30) receives theCA_DET event packet via the communications link (32), local link mediuminterface (44) and local link medium channel (43). In response to theCA_DET event packet, the local controller (40) re-configures the localCA_DET channel (39) to an upstream output direction and indicates to thelocal DisplayPort interface (35) that a cable adapter is present.

FIG. 7 is a block diagram showing the configuration of the cable-detectsignals when a sink-side cable adapter (17) is attached to the upstreaminterface of the system shown in FIG. 5. FIG. 7 depicts a sink-sidecable adapter (17) connected to the LPU (30) via DisplayPort connector(22), DisplayPort cable (23) and local DisplayPort interface (35). Thelocal CA_DET channel (39) is asserted by the sink-side cable adapter(17) and the local controller (40) observes that a cable adapter isconnected. The local controller (40) generates and transmits a CA_DETevent packet to the RPU (31) via the local link medium channel (43) andlocal link medium interface (44). The RPU (31) receives the CA_DET eventpacket via the communications link (32), remote link medium interface(45) and remote link medium channel (47). In response to the CA_DETevent packet, the remote controller (48) re-configures the remote CA_DETchannel (51) to an downstream output direction and indicates to theremote DisplayPort interface (52) that a cable adapter is present.

FIG. 8 shows a timing diagram demonstrating a first instance of DDCclock stretching (as previously mentioned) as used by the localcontroller (40) in order to delay in responding to the source device.The source device (DVI/HDMI or DisplayPort Dual-mode source device)transmits data over the DDC data channel (53) over eight DDC clock (54)cycles. After the eight clock cycle, the DDC clock is driven by thelocal controller (40) which holds the DDC clock (54) low until it isready to respond. When the local controller (40) is ready to respond,the local controller (40) drives the DDC clock (54) during theacknowledgement cycle of the DDC protocol while responding with anacknowledge or not-acknowledge signal over the DDC data channel (53).The source device is free to continue transmitting data to the LPU (30)only after the acknowledgement clock cycle, and as such, the timing ofthe transmission is stretched. This allows the transmission to continueeven though delays (such as those caused by longer cable lengths thanthose allowed under the guidelines, may be used.

FIG. 9 shows a timing diagram demonstrating a second instance of DDCclock stretching used by the local controller (40) to delay inresponding to the source device. The source device transmits data overthe DDC data channel (53) over eight DDC clock (54) cycles. After theeight clock cycle, the DDC clock (54) is driven by the local controller(40) which holds the DDC clock (54) low until it is ready to respond.When the local controller (40) is ready to respond, the local controller(40) drives the DDC clock (54) during the acknowledgement cycle of theDDC protocol while responding with an acknowledge or not-acknowledgeover the DDC data channel (53). The local controller (40) will hold theDDC clock (54) low until it is ready to respond again. When the localcontroller (40) is ready to respond, the local controller (40) drivesthe DDC clock (54) and transmits data over the DDC data channel (53) tothe source device.

FIG. 10 shows a timing diagram demonstrating a third instance of DDCclock stretching used by the local controller (40) to delay inresponding to the source device. The local controller (40) transmitsdata over the DDC data channel (53) over eight DDC clock (54) cycles tothe source device and the source device transmits an acknowledge ornot-acknowledge signal over the DDC data channel (53) during theacknowledgement cycle of the DDC protocol. After the acknowledgementcycle, the DDC clock is driven by the local controller (40) which holdsthe DDC clock (54) low until it is ready to respond. When the localcontroller (40) is ready to respond, the local controller (40) drivesthe DDC clock (54) and transmits data over the DDC data channel (53) tothe source device.

The methods of the system with respect to the DDC component of theDVI/HDMI information are illustrated by way of sequence diagrams shownin FIGS. 11 & 12, in which passage of time is represented in thedownward direction from top to bottom, and electronic communicationsbetween devices is represented by arrows in the horizontal or nearhorizontal direction from side to side of such sequence diagrams. Insequence diagrams of FIGS. 11 & 12, DDC signals present at the sourcedevice are indicated at various points along the vertical time axis (55)positioned directly beneath the “SOURCE SIDE” header. Similarly, DDCsignals present at the LPU (30) are indicated at various points alongthe vertical time axis (56) positioned directly beneath the “LPU”header. Continuing similarly, DDC signals present at the RPU (31) areindicated at various points along the vertical time axis (57) positioneddirectly beneath the “RPU” header, and DDC signals present at the sinkdevice are indicated at various points along the vertical time axis (58)positioned directly beneath the “SINK SIDE” header. The source devicecan be any DVI/HDMI source device (16) connected to a sink-side cableadapter (17) or a DisplayPort Dual-mode source device (2). The sinkdevice can be any DVI/HDMI sink device (4) connected to a source-sidecable adapter (3) or a DisplayPort Dual-mode sink device (18).

The sequence diagram shown in FIG. 11 demonstrates an example of a DDCwrite transaction according to the present invention. As indicated bythe uppermost and leftmost arrow of FIG. 11, DDC information consistingof a DDC write command (START bit, ADDRESS, WRITE bit) is delivered tothe LPU (30). The LPU (30) will drive the DDC clock (54) low asdescribed in the first instance of DDC clock stretching shown in FIG. 8.Periods of DDC clock stretching are indicated on FIG. 11 by the hashmarkings on the LPU vertical time axis (56). The LPU (30) will transmita DDC request packet to the RPU (31) over the link medium (32). The RPU(31) regenerates the original DDC information using proper DDC protocoland transmits it to the sink device. The sink device responds with anacknowledgement bit which the RPU (31) transmits to the LPU (30) in theform of a DDC response packet. The LPU (30), after receiving theresponse packet, drives the DDC clock (54) and transmits the originalDDC information using proper DDC protocol to the source device. Thesource device continues by sending data to the LPU (30) which the LPU(30) creates and transmits a DDC request packet to the RPU (31). The LPU(30) repeats in driving the DDC clock (54) low, again as shown in FIG.8. The RPU (31) continues to transmit DDC information to the sink deviceand creates DDC response packets in response to DDC information itreceives from the sink device. This process of data transmission maycontinue indefinitely even though FIG. 11 displays only two datatransmission by the source device. The transaction is terminated when aSTOP is received by the LPU (30). DDC clock stretching is notimplemented since it is not needed for the STOP information. The STOPinformation is send to the RPU (31) for transmission to the sink device,in the same manner described above.

The sequence diagram shown in FIG. 12 demonstrates an example of a DDCread transaction according to the present invention. As indicated by theuppermost and leftmost arrow of FIG. 12, DDC information consisting of aDDC read command (START bit, ADDRESS, READ bit) is delivered to the LPU(30). The LPU (30) will drive the DDC clock (54) low as described in thesecond instance of DDC clock stretching, as shown and described in FIG.9. Periods of DDC clock stretching are indicated on FIG. 12 by the hashmarkings on the LPU vertical time axis (56). The LPU (30) will transmita DDC request packet to the RPU (31) over the link medium (32). The RPU(31) regenerates the original DDC information using proper DDC protocoland transmits it to the sink device. The sink device responds with anacknowledgement bit which the RPU (31) transmits to the LPU (30) in theform of a DDC response packet. The LPU (30), after receiving theresponse packet, drives the DDC clock (54) and transmits theacknowledgment bit using proper DDC protocol to the source device. TheDDC clock stretching is continued as specified in the second instance ofDDC clock stretching. The sink device responds with DDC data which theRPU (31) transmits to the LPU (30) in the form of a DDC response packet.The LPU (30), after receiving this response packet, drives the DDC clock(54) and regenerates the DDC data using proper DDC protocol andtransmits it to the source device. The LPU (30) receives an acknowledgebit from the source device and implements the third instance of clockstretching. The LPU (30) sends the acknowledge bit in the form of a DDCrequest packet to the RPU (31)). The RPU (31) regenerates the originalDDC information using proper DDC protocol and transmits it to the sinkdevice. The sink device responds with DDC data which the RPU (31)transmits to the LPU (30) in the form of a DDC response packet. Thisprocess of data transmission may continue indefinitely even though FIG.12 displays only two data transmissions by the sink device. Thetransaction is terminated when a STOP or NACK is received by the LPU(30). DDC clock stretching is not implemented. The STOP information issend to the RPU (31) for transmission in the same manner describedabove.

Referring to FIG. 13, the proxy features of the system advantageouslypermits the system to communicate foreign data communications (i.e. datacommunications which are non-compatible with the DisplayPortspecification for Dual-mode devices) from foreign devices along thecommunications link (32). The DDC bandwidth, in some instances, requires100 kbps, and the LPU (30), the communications link (32), and the RPU(31) are operable in some embodiments to communicate in accordance witha bandwidth greater than 100 kbps. However, the combined bandwidth ofthe local link medium channel (43), the communications link (32), andthe remote link medium channel (47) in some embodiments is 720 Mbps orhigher. Thus, the system advantageously permits the communication ofboth DVI/HDMI information and foreign device information along a commoncommunications link, such as the communications link (32) shown in FIGS.13 & 14.

Foreign information may be any information in a form compliant with anyprotocol, including USB (Universal Serial Bus) or other serialprotocols, other parallel protocols, Ethernet, other standardcommunication protocols, custom communication protocols, or anycombination thereof for example.

FIG. 13 is a block diagram of a system for communicating videoinformation between a source device compatible with the DisplayPortspecifications for Dual-mode devices and a sink device that is notcompatible with the DisplayPort Specifications across a duplexcommunication link wherein foreign data may be combined with theDisplayPort Dual-mode signals, according to the current invention. FIG.13 shows a system (59) demonstrating a further embodiment of theinvention consisting of a DisplayPort Dual-mode source device (2), LPU(30), communications link (32), RPU (31), Source-side cable adapter (3),and DVI/HDMI sink device (4) as configured in a similar form to theembodiment shown in FIG. 3. Additionally, the system (59) consists of alocal foreign device (60) and remote foreign device (69). The LPU (30)is operable to connect to a local foreign device (60) having a localforeign device connector (61) for receiving a local foreign cable (62).The local foreign device (60) can be any system capable of electroniccommunications. The local foreign cable (62) is shown in FIG. 13 beingattached to the local foreign device interface (63) of the LPU (64). Alocal foreign channel (64) of the LPU (30) is operable to transferforeign information between the local foreign device interface (63) andthe local controller (40).

Also, a remote foreign channel (65) of the RPU (31) is connected betweenthe remote controller (48) and a remote foreign device interface (66) ofthe RPU (31). The remote foreign device interface (66) is shown in FIG.13 being attached to a remote foreign cable (67) which is received bythe remote foreign device connector (68) of the remote foreign device(69).

Communications between the local and remote foreign devices (60 & 69)are not limited to one-way communications. In some instances, the system(59) is operable to communicate foreign information via thecommunications link (32) uni-directionally, uni-directionally in theopposite direction, or bi-directionally.

In the case of bi-directional communications, the local controller (40)is operable to receive foreign information from the local foreignchannel (64) and produce one or more foreign packets in response toreceived foreign information. The local controller (40) transmitsforeign packets to the RPU (31) via the communications link (32), whichmay include transmitting foreign packets by interleaving foreign packetsand DVI/HDMI request packets. In addition, local controller (40)receives foreign packets from the local link medium channel (43) andproduces representative foreign information in response to the receivedforeign packet received from the RPU (31) from the remote foreign device(69). The local controller (40) outputs the representative foreigninformation to the local foreign channel (64) for delivery to the localforeign device (60).

Similarly, the remote controller (48) is operable to receive foreigninformation from the remote foreign channel (65) and produce one or moreforeign packets in response to received foreign information. The remotecontroller (48) transmits foreign packets to the LPU (30) via thecommunications link (32), which may include transmitting foreign packetsby interleaving foreign packets and DVI/HDMI response packets. Inaddition, remote controller (48) receives foreign packets from theremote link medium channel (47) and produces representative foreigninformation in response to the received foreign packet received from theLPU (30) from the local foreign device (60). The remote controller (48)outputs the representative foreign information to the remote foreignchannel (65) for delivery to the remote foreign device (69).

It will be understood, however, that the system (59) of FIG. 13 isoperable to communicate DVI/HDMI information in the manner describedherein above in respect of the embodiment of FIG. 3.

FIG. 14 shows a system (70) demonstrating a further embodiment of theinvention consisting of a DVI/HDMI source device (16), Sink-side cableadapter (17), LPU (30), communications link (32), RPU (31), andDisplayPort Dual-mode sink device (18) as configured in a similar formto the embodiment shown in FIG. 4. Additionally, the system (70)consists of a local foreign device (60) and remote foreign device (69).The LPU (30) is operable to connect to a local foreign device (60)having a local foreign device connector (61) for receiving a localforeign cable (62). The local foreign device (60) can be any systemcapable of electronic communications. The local foreign cable (62) isshown in FIG. 14 being attached to the local foreign interface (63) ofthe LPU (64). A local foreign channel (64) of the LPU (30) is operableto transfer foreign information between the local foreign interface (63)and the local controller (40).

Also a remote foreign channel (65) of the RPU (31) is connected betweenthe remote controller (48) and a remote foreign interface (66) of theRPU (31). The remote foreign interface (66) is shown in FIG. 13 beingattached to a remote foreign cable (67) which is received by the remoteforeign device connector (68) of the remote foreign device (69).

As with the embodiment of the invention described in FIG. 13,communications between the local and remote foreign devices (60 & 69)are not limited to one-way communications. In some instances, the system(59) is operable to communicate foreign information via thecommunications link uni-directionally, uni-directionally in the oppositedirection, or bi-directionally.

The system (70) is operable to communicate foreign information in themanner described herein above in respect to the third embodiment, thefourth embodiment, either or both of the third and fourth embodiment, orvariations thereof for example.

It will again be understood, however, that the system (70) of FIG. 14 isoperable to communicate DVI/HDMI information in the manner describedherein above in respect of the embodiment of FIG. 4.

The interleaving of foreign packets and DVI/HDMI request or responsepackets in the embodiments shown in FIGS. 13 and 14 shows one examplewhere the local and remote controller (40 & 48) performed themultiplexing and de-multiplexing of the foreign information and DVI/HDMIinformation. FIG. 15 demonstrates an alternate method where themultiplexing and de-multiplexing of the foreign information and DVI/HDMIinformation is performed by a local and remote link medium controller(71 & 73). The local controller (40) creates and transmits requestpackets to a local dual-mode channel (72) connected to the local linkmedium controller (71). The local foreign device interface (63) isconnected to the local link medium controller (71) by the local foreignchannel (64). The local link medium controller (71) is operable bycreating link medium packets consisting of foreign information andDVI/HDMI information to be outputted to the local link medium channel(43). These packets may be interleaved, in any known and suitablemanner. These link medium packets are transferred to the remote unit(31) via the communications link (32) to be transmitted to the correctdestination (foreign device (69) or sink device).

The local link medium controller (71) is also operable by receiving linkmedium packets and determining the destination of the containedinformation. Response packets are forwarded to the local controller (40)over the local dual-mode channel (72). Information destined for thelocal foreign device (60) is regenerated and outputted over the localforeign channel (64).

Conversely, the remote controller (48) creates and transmits responsepackets to a remote dual-mode channel (74) connected to the remote linkmedium controller (73). The remote foreign device interface (66) isconnected to the remote link medium controller (73) by the remoteforeign channel (65). The remote link medium controller (73) is operableby creating link medium packets consisting of foreign information andDVI/HDMI information to be outputted to the remote link medium channel(47). These packets may be interleaved. These link medium packets aretransferred to the local unit (30) via the communications link (32) tobe transmitted to the correct destination (foreign device (60) or sourcedevice). The remote link medium controller (73) is also operable byreceiving link medium packets and determining the destination of thecontained information. Request packets are forwarded to the remotecontroller (48) over the remote dual-mode channel (74). Informationdestined for the remote foreign device (69) is regenerated and outputtedover the remote foreign channel (65).

Thus, it is apparent that there has been provided, in accordance withthe present invention, a DisplayPort device which fully satisfies thegoals, objects, and advantages set forth hereinbefore. Therefore, havingdescribed specific embodiments of the present invention, it will beunderstood that alternatives, modifications and variations thereof maybe suggested to those skilled in the art, and that it is intended thatthe present specification embrace all such alternatives, modificationsand variations as fall within the scope of the appended claims.

Additionally, for clarity and unless otherwise stated, the word“comprise” and variations of the word such as “comprising” and“comprises”, when used in the description and claims of the presentspecification, is not intended to exclude other additives, components,integers or steps. Further, the invention illustratively disclosedherein suitably may be practiced in the absence of any element which isnot specifically disclosed herein.

Moreover, the words “substantially” or “essentially”, when used with anadjective or adverb is intended to enhance the scope of the particularcharacteristic; e.g., substantially planar is intended to mean planar,nearly planar and/or exhibiting characteristics associated with a planarelement.

Further, use of the terms “he”, “him”, or “his”, is not intended to bespecifically directed to persons of the masculine gender, and couldeasily be read as “she”, “her”, or “hers”, respectively.

Also, while this discussion has addressed prior art known to theinventor, it is not an admission that all art discussed is citableagainst the present application.

The invention claimed is:
 1. A method for communicating DisplayPortdual-mode signals and information and for communicating foreigninformation from a foreign source device between an originating unit anda terminating unit across a dual simplex communications link, saidmethod comprising: a) receiving at a local unit dual-mode signals froman originating unit; b) converting at said local unit said receiveddual-mode signals into one or a plurality of request data packets; c)transmitting at said local unit said one or a plurality of request datapackets to a remote unit across said dual simplex communications link;d) receiving at said remote unit said transmitted one or a plurality ofrequest data packets as one or a plurality of received request datapackets; e) converting at said remote unit said one or a plurality ofreceived request data packets into converted dual-mode signals; f)transmitting at said remote unit said converted dual-mode signals to aterminating unit; g) receiving at said remote unit dual-mode signalsfrom said terminating unit; h) converting at said remote unit saidreceived dual-mode signals into one or a plurality of response datapackets; i) transmitting at said remote unit said one or a plurality ofresponse data packets to said local unit across said dual simplexcommunications link; j) receiving at said local unit said transmittedone or a plurality of response data packets as one or a plurality ofreceived response data packets; k) converting at said local unit saidone or a plurality of received response data packets into converteddual-mode signals; and l) transmitting at said local unit said converteddual-mode signals to said originating unit, and wherein said methodfurther comprises: i) receiving at said local unit foreign informationfrom a foreign source device; ii) converting at said local unit saidreceived foreign information into one or a plurality of foreign requestdata packets; iii) transmitting at said local unit said one or aplurality of foreign request data packets to said remote unit acrosssaid dual simplex communications link; iv) receiving at said remote unitsaid transmitted one or a plurality of foreign request data packets asone or a plurality of received foreign request data packets; v)converting at said remote unit said one or a plurality of foreignreceived request data packets into converted foreign information; vi)transmitting at said remote unit said converted foreign information to aforeign destination device; vii) receiving at said remote unit foreigninformation from said foreign destination device; viii) converting atsaid remote unit said received foreign information into one or aplurality of foreign response data packets; vix) transmitting at saidremote unit said one or a plurality of foreign response data packets tosaid local unit across said dual simplex communications link; x)receiving at said local unit said transmitted one or a plurality offoreign response data packets as one or a plurality of received foreignresponse data packets; xi) converting at said local unit said one or aplurality of foreign received response data packets into convertedforeign information; and xii) transmitting at said local unit saidconverted foreign information to said foreign source device.
 2. A methodas in claim 1 wherein said originating unit and/or said terminating unitis a Dual-mode device, which device conforms to the DisplayPortSpecifications and DisplayPort Interoperability Guidelines.
 3. A methodas in claim 1 wherein said originating unit is a DVI 1.0 or HDMI devicewith an attached Sink-Side Cable Adapter and/or said terminating unit isa DVI 1.0 or HDMI device with an attached Source-Side Cable Adapter, andwherein said device and/or said adapter conforms to the DisplayPortSpecifications and DisplayPort Interoperability Guidelines.
 4. A methodas in claim 1 wherein said DisplayPort dual-mode signals and informationcomprise Hot Plug Detect, Cable Adapter Detect and Display Data Channelinformation.
 5. A method as in claim 1 wherein one or a plurality ofdownstream request data packets are transmitted across a first simplexchannel of said dual-simplex communications link and one or a pluralityof upstream request data packets are transmitted across a second simplexchannel of said dual-simplex communications link.
 6. A method of claim 1further comprising delaying a DDC response to a Dual-mode or DVI or HDMIsource unit or Cable Adapter by clock stretching.
 7. A method of claim 6wherein clock stretching is implemented by: delaying the acknowledgementphase of a DDC transaction; delaying the beginning of a data phase afteran acknowledgement phase of a DDC transaction; or delaying theacknowledgement phase and the beginning of a data phase after anacknowledgement phase of a DDC transaction.
 8. A method of claim 1further comprising upon connection to the Dual-mode environment,performing by said remote unit an operation to read static DVI or HDMIinformation from said terminating unit and transmitting said informationto said local unit.
 9. A method of claim 8 further comprising uponconnection to the Dual-mode environment, performing by said local unitan operation of storing said static DVI or HDMI information receivedfrom said remote unit.
 10. A method of claim 9 further comprising atsaid local unit, receiving a request from said originating unit forstatic DVI or HDMI information, determining that the informationpertaining to said request is stored in local memory, selecting saidpertinent information from said stored information and transmitting saidselected information to said originating unit.
 11. A method of claim 1wherein said local unit and said remote unit detects the presence of aDual-mode Cable adapter and transmits such information to said remoteunit and said local unit.
 12. A method of claim 1 wherein said remoteunit detects the presence of a Dual-mode or DVI or HDMI sink unit andtransmits such information to said local unit.
 13. A system forcommunicating DisplayPort dual-mode signals and information and forcommunicating foreign information from a foreign source device betweenan originating unit and a terminating unit across a dual simplexcommunications link, said system comprising of: a) a local unitcomprising a local controller operable to: a) receive from anoriginating unit dual-mode signals; b) convert said received dual-modesignals into one or a plurality of request data packets; c) transmitsaid one or a plurality of request data packets to a remote unit acrosssaid dual simplex communications link; d) receive one or a plurality ofresponse data packets from said remote unit across said dual simplexcommunications link; e) convert said received one or a plurality ofresponse data packets into converted dual-mode signals; and f) transmitsaid converted dual-mode signals to said originating unit, and b) aremote unit comprising a remote controller operable to: a) receive saidone or a plurality of request data packets from said local unit acrosssaid dual simplex communications link; b) convert said received one orplurality of request data packets into converted dual-mode signals; c)transmit said converted dual-mode signals to a terminating unit; d)receive from said terminating unit dual-mode signals; e) convert saidreceived dual-mode signals into said one or a plurality of response datapackets; and f) transmit said one or a plurality of response datapackets across said dual simplex communications link and wherein saidlocal controller of said local unit is also operable to: i) receiveforeign information from a foreign source device; ii) convert saidreceived foreign information into one or a plurality of foreign requestdata packets; iii) transmit said one or a plurality of foreign requestdata packets to said remote unit across said dual simplex communicationslink; iv) receive transmitted one or a plurality of foreign responsedata packets as one or a plurality of received foreign response datapackets; v) convert said one or a plurality of foreign received responsedata packets into converted foreign information; and vi) transmit saidconverted foreign information to said foreign source device, and saidremote controller of said remote unit is also operable to: i) receivesaid transmitted one or a plurality of foreign request data packets asone or a plurality of received foreign request data packets; ii) convertsaid one or a plurality of foreign received request data packets intoconverted foreign information; iii) transmit said converted foreigninformation to a foreign destination device; iv) receive foreigninformation from said foreign destination device; v) convert receivedforeign information into said one or a plurality of foreign responsedata packets; and vi) transmit said one or a plurality of foreignresponse data packets to said local unit across said dual simplexcommunications link.
 14. A system as in claim 13 wherein saidoriginating unit and/or said terminating unit is a Dual-mode device,conforming to the DisplayPort Specifications and DisplayPortInteroperability Guidelines.
 15. A system as in claim 13 wherein saidoriginating unit is a DVI 1.0 or HDMI device with an attached Sink-SideCable Adapter, and/or said terminating unit is a DVI 1.0 or HDMI devicewith an attached Source-Side Cable Adapter which device and adapterconform to the DisplayPort Specifications and DisplayPortInteroperability Guidelines.
 16. A system as in claim 13 wherein saidDisplayPort dual-mode signals comprise Hot Plug Detect, Cable AdapterDetect and Display Data Channel information.
 17. A system as in claim 13wherein one or a plurality of downstream request data packets aretransmitted across a first simplex channel of said dual-simplexcommunications link and one or a plurality of upstream request datapackets are transmitted across a second simplex channel of saiddual-simplex communications link.
 18. A system of claim 13 wherein saidlocal controller is operable to operate a queue of memory of said localunit.
 19. A system of claim 13 wherein said local controller is operableto select and output from said local unit, data selected from the groupconsisting of stored representative dual-mode information and receivedresponse data packet from said remote unit.